Dear editor,

China has undergone tremendous economic growth,but there still remains much room for improvement in emergency medical service (EMS) system.[1] The EMS in China comprises of three parts: the pre-hospital emergency service, the emergency department, and the intensive care unit. Not much is known about the exact numbers of out-of-hospital cardiac arrest (OHCA)across the whole of China, though there are reports from specific provinces. Due to differences in methods of data collection and data definitions, it is difficult to make comparisons among provinces or summarize the total data, therefore, it is necessary to describe characteristics and outcomes of OHCA within one province.

Zhejiang province located on China's southeastern coast covers a total land area of 101,800 square kilometers with a population of approximately 8.8 million at the end of 2014. There were 689 ambulances in 68 emergency centers and only 28.2% of ambulances are equipped with defibrillators. An ambulance includes 3 EMS staff members, including at least 1 emergency physician.Emergency physicians are trained to perform various resuscitation methods, like semi-automated external defibrillators, intubation, insertion of a peripheral intravenous line, and administration of drugs such as epinephrine in situations of cardiac arrest.

结果显示，干预1学年后，教师对儿童进行体力活动的态度发生改变，经常鼓励儿童进行体力活动的比例明显高于干预前，差异有显著性(P=0.000)。见表4。但家长对儿童进行体力活动的态度没有明显变化，差异无显著性(P=0.471)。

Zhejiang Provincial People's Hospital is one of the largest comprehensive hospitals in Zhejiang province,which provides medical care with more than 2,000 beds and has 150,000 visits to emergency departments annually. Ningbo and Shaoxing are two of the most important cities in Zhejiang province. Ningbo EMS Center serves a population of approximately 5,830,000 around Ningbo City, while Shaoxing EMS Center serves approximately 4,430,000 people around Shaoxing City.

Our study aimed to summarize characteristics and outcomes of OHCA in Zhejiang province, based on the OHCA cases presenting to Zhejiang Provincial People's Hospital, Ningbo EMS Center, and Shaoxing EMS Center.

METHODS

Study setting and design

This is an observational, retrospective, multi-center study based on the identification and analysis of records of OHCA patients during the period between January 1, 2012 and January 31, 2016. The data was collected from the three EMS centers. Data was collected in accordance with the recommended guidelines[2] for uniform reporting of data from out-of-hospital cardiac arrest, including sex, age, past medical history, location of arrest, course of resuscitation, presence of witnesses,pre-hospital drug administration, first arrest rhythm,bystander cardiopulmonary resuscitation (CPR), return of spontaneous circulation (ROSC), hospital admission,and hospital discharge. After completion by the EMS personnel, the data form was integrated into the registry system, and checked by the investigators. If the data sheet was incomplete, the relevant EMS personnel were contacted and questioned for data completion.

The statistical package for social sciences (SPSS),version 19.0, (IBM, New York, New York, USA) was used for data entry and analyses. Descriptive analyses were carried out by calculating the number and percentage for categorical variables, whereas mean±SD were calculated for continuous variables.

The 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care[3] was adapted for the resuscitation protocol. Bystander CPR included chest compressiononly CPR and conventional CPR with rescue breathing.ROSC refers to the regaining of palpable pulse.

Statistical analysis

1.2.4图像分析 由我科两名经验丰富的医生进行分析，并达成共识，评价不一致时重新观察原始图像及重建图像，最后得出一致结论，伪影严重者需以MIP、CP为主，并结合MPR和VR后处理图像来综合评估，分析其产生的原因及存在的技术缺陷，提出解决方法。

RESULTS

Funding: None.

Our study has limitations. Due to the lack of follow up, we could not ascertain the long-term outcome of patients who survived at discharge. Another limitation is that pre-hospital information was obtained from the EMS records where documentation was inconsistent and incomplete. The third limitation is that the data was only from one hospital and two EMS centers in Zhejiang province.

Table 1. Characteristics of patients with OHCA, n (%)

Characteristics　OHCA (n=332)Age [mean (±SD)] (years)　 58 (±20.8)Male sex　233 (70.2)Past medical history Heart disease　 60 (18.1)Hypertension　 61 (18.4)Diabetes mellitus　 25 (7.5)Cancer　 15 (4.5)Chronic obstructive pulmonary disease　 14 (4.2)Location of arrest Home residence　220 (66.3)Healthcare facility　 8 (2.4)Public/commercial building　 27 (8.1)Street/highway　 44 (13.3)Industrial place　 18 (5.4)Place of recreation　 9 (2.7)Others　 6 (1.8)Arrest witnessed Arrest witnessed by bystander　253 (76.2)Arrest witnessed by EMS personnel　 16 (4.8)Arrest not witnessed　 63 (19.0)Pre-hospital resuscitation CPR by bystander　 11 (3.3)CPR by EMS personnel　283 (85.2)CPR not attempted　 38 (11.4)defibrillation attempted　 28 (8.4)defibrillation not attempted　304 (91.6)Intubation attempted　 60 (18.1)Intubation not attempted　272 (81.9)Pre-hospital drug administration Epinephrine　173 (52.1)Sodium bicarbonate　 20 (6.0)Atropine　 6 (1.8)First arrest rhythm VF/VT　 23 (6.9)PEA　 19 (5.7)Asystole　244 (73.5)Unknown　 46 (13.9)

In this study, the arrests were classified as trauma origin and non-trauma origin (cardiac etiology,respiratory diseases, electrocution, drowning and other causes). These diagnoses were made clinically by the physician in charge in collaboration with the EMS personnel. Totally 103 (31.0%) patients had trauma arrest and 229 (69.0%) had non-trauma arrest. Cardiac etiology(43.4%) was the top causes in the subgroup of nontrauma (Table 2).

In this study, we found only a small number of patients (3.3%) received CPR performed by bystanders.The rate was lower than that reported in other Asian countries, 10.5% in United Arab Emirates, 40.2% in Japan,and 40.9% in Republic of Korea.[6] This indicated that the basic knowledge and skills of CPR are comparatively poor in our cities, therefore it is urgent to train people to perform CPR when facing CA patients.[7] A telephoneassisted CPR program[8] is recommended. Only 4.8%patients received pre-hospital defibrillations. The rate was also lower than that of most Asian countries except Malaysia (2.6%). The reason may be that automated external defibrillators (AEDs) are rarely available in public places or ambulances in Zhejiang province,and not every EMS personnel could operate an AED.Endotracheal intubation has long been regarded as the"gold standard" for cardiac arrest, which may improve outcome in patients who arrest. In our study, pre-hospital intubation was attempted only in 18.1% patients.

DISCUSSION

Only ten (3.0%) patients showed ROSC at scene or en-route and 37 (11.1%) patients showed ROSC at ED. The survival rate to hospital discharge for OHCA victims was low (2.1%). This overall survival rate was lower than the previously reported rates in countries with developed EMS systems.[9,10] In the future, we can train more people to perform bystander CPR, and introduce AEDs in ambulances and public places.

In Zhejiang province, many efforts have been made to improve the survival rate, like reducing the EMS response time, regular CPR training for the EMS staff and emergency physicians, and early implementation of the current CPR guidelines. Because of the lack of favorable evidence, sodium bicarbonate administrationduring adult and pediatric CPR is not recommended, but it was still the second most used pre-hospital drug after epinephrine as a conventional equipment in ambulances,particularly in many rural areas of Zhejiang province.

Table 2. The causes of OHCA

Cause of arrest　n (%)Trauma　103 (31.0)Non-trauma　229 (69.0)Cardiac etiology　144 (43.4)Respiratory　 14 (4.2)Electrocution　 6 (1.8)Drowning　 12 (3.6)Others　 53 (16.0)

Table 3. Overall outcomes of OHCA

Outcomes　n (%)ROSC at scene/en-route　10 (3.0)ROSC at ED　37 (11.1)Admission to hospital　27 (8.1)Survival to hospital discharge　 7 (2.1)

Ten patients had ROSC at scene/en-route and 37 had ROSC at ED. Only 27 patients were admitted to the hospital. At discharge, only 7 (2.1%) patients survived(Table 3).

OHCA is a leading cause of death in the industrialized world.[3,4] The development of a public-access defibrillation system and revisions to CPR guidelines have increased survival rate after OHCA in some countries, but the outcomes of OHCA in China remains poor.[5]

Limitations

ISO公制螺栓强度等级标号是由两部分数字组成，分别表示螺栓材料的公称抗拉强度值和屈强比值。例如4.8级的螺栓，其含义是此螺栓的抗拉强度为400MPa；螺栓材质的屈强比值为0.8，屈服强度为400×0.8=320MPa。

CONCLUSION

The OHCA survival in Zhejiang is comparatively low. Several key elements for improving survival rate, like bystander CPR and early defibrillation in OHCA victims,should be emphasized.

During the study period, there were a total of 353 OHCA cases recorded in the three EMS centers. Twenty one (5.9%) cases were excluded because they were transferred to EMS centers not by ambulances thus lacking prehospital records. Demographic data including age, sex and past medical history are listed in Table 1.More than half OHCA occurred in home. A total of 253 (76.2%) patients were witnessed by bystanders,while bystander CPR was performed only in 11 (3.3%)cases. CPR was mainly performed by EMS personnel(283, 85.2%). Only 28 (8.4%) patients underwent prehospital defibrillation, and pre-hospital intubations was attempted in 60 (18.1%) patients. Epinephrine was the most frequently used drugs (52.1%) in an out-of-hospital environment. Asystole was the predominant rhythm(73.5%).

为了在更小的电活动程度和更大的数量上进行测量，20世纪60年代，科学家开始设想是否可以设计一种感受器或探针，在电信号的作用下能够发出荧光。最常用的探针是钙指示剂，当电活动产生峰电位时，钙离子流入神经元，而钙指示剂在结合钙离子后发光。但钙离子成像这一技术仅仅能间接反映细胞电活动，并不能直接记录细胞膜电位。同时，尽管它能记录动作电位这种较为剧烈的电位变化，仍然对微小的膜电位变化或抑制了动作电位的电信号充耳不闻。这又如同是仅仅听到交响乐结束后的掌声震耳欲聋，显然演出这一事件发生了，但演奏内容不得而知。

Ethical approval: The study was approved by the Institutional Review Board.

研究过程中，主要采取相对均匀的林地进行造林，前茬以杉木纯林为主，初植密度为2 500株/hm2。样地的基本情况如表1所示。

Conflicts of interest: The authors declare that there are no conflicts of interest regarding the publication of this paper.

Contributors: MF proposed the study, analyzed the data and wrote the first drafts. All authors contributed to the design and interpretation of the study and to further drafts.

How do the power relations among all speakers affect turntaking organization in this reversion of If You Are the One?

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